The present invention relates to precision electrical measurement systems and, in particular, to cabling for measurement systems.
Semiconductor device characterization requires a diverse array of measurements in order to understand a semiconductor device's electrical characteristics and to understand the processes used to manufacture it. IV, CV, and pulse-based measurements are the most common measurements made. It is valuable to strive to integrate these measurements in order to reduce the time and effort required to make these measures. One of the most difficult problems associated with integrating these measurements is that the cabling required for each measurement type is fundamentally different.
Cabling for precision DC measurements tends to focus on forcing and sensing electrical values as physically close to the device under test (DUT) as possible and trying to minimize leakage currents through such techniques as guarding conductors with adjacent conductors having an equal potential. A coaxial cable can be used for this by forcing and measuring on center conductors and guarding on the coaxial conductor.
Cabling for high frequency (HF) measurements such as RF and pulse measurements have a substantial focus on providing a characteristic impedance that matches that of the measurement instrument.
Referring to FIG. 1, cabling for a pulse measurement system 1 has the outer coaxial conductors of the cables at the DUT ends of the cables tied together to provide the HF ground 2 on the DUT.
This connection of the outer coaxial conductors to the DUT is in general opposition to DC measurements where typically only the center conductors are connected to the DUT.